Heavy water moderated molten salt reactor

Abstract

The invention provides a heavy water moderated molten salt reactor, and relates to the technical field of nuclear reactors. The heavy water moderated molten salt reactor comprises a reactor container and a reactor core, the reactor container is provided with a molten salt inlet and a molten salt outlet, and the molten salt inlet and the molten salt outlet are both located in the lower portion of the reactor container; the reactor core is located in the reactor container, the reactor core comprises a molten salt channel and a heavy water containing space, the heavy water containing space wraps the molten salt channel and is filled with heavy water, and the molten salt channel is connected between the molten salt inlet and the molten salt outlet. The liquid heavy water is adopted to replace solid graphite to serve as the moderator, on one hand, the moderation requirement of the molten salt reactor is met, on the other hand, the problems of irradiation swelling and regular replacement of the solid moderation material can be solved, and the intrinsic safety of the nuclear power plant is improved.

Description

Technical Field

[0001] The present application relates to the technical field of nuclear reactors, and in particular to a heavy water moderated molten salt reactor. Background Art

[0002] Nuclear power is an important component of clean energy. Most of the current nuclear reactors use uranium, but the cost of natural uranium continues to rise, and there are risks in the supply and cost control of uranium resources. Thorium-based molten salt reactors are a type of reactor that achieves efficient utilization of thorium fuel. The development of thorium-based molten salt reactors can effectively improve the supply and cost control capabilities of nuclear fuel and ensure energy security.

[0003] Molten salt reactors usually use liquid fuel, directly dissolving nuclear fuel in molten salt. The fuel molten salt circulates in the core and the primary pipeline, serving as both fuel and coolant. Molten salt reactors generally use graphite moderation, which can effectively utilize thorium-based fuel. By optimizing the core layout, nuclear fuel proliferation utilization under the thermal spectrum can be achieved.

[0004] Nuclear safety is a prerequisite for the development of nuclear energy. After the Fukushima accident in Japan, the importance of passive safety systems has become increasingly prominent. The passive safety concept refers to the use of natural forces, such as gravity, natural convection, diffusion, etc., without the intervention of external power sources, to ensure the safety of nuclear power plants under normal and accident conditions, to simplify the system, reduce the probability of accidents caused by equipment failures and human errors, and improve the safety of nuclear power plants. The primary circuit of the thorium-based molten salt reactor is at normal pressure and has a certain inherent safety. Summary of the invention

[0005] In view of this, the present application provides a heavy water moderated molten salt reactor to improve the intrinsic safety of nuclear power plants.

[0006] In a first aspect, the present application provides a heavy water moderated molten salt reactor, comprising: A reactor vessel having a molten salt inlet and a molten salt outlet, wherein the molten salt inlet and the molten salt outlet are both located at a lower portion of the reactor vessel; A core is located in the reactor vessel, the core comprising a molten salt channel and a heavy water containing space, the heavy water containing space wraps the molten salt channel and is filled with heavy water, and the molten salt channel is connected between the molten salt inlet and the molten salt outlet.

[0007] In a possible implementation, the molten salt channel includes a first molten salt channel and a second molten salt channel, the first molten salt channel has a first end and a second end, the second molten salt channel has a third end and a fourth end, the first end is connected to the molten salt inlet, the second end is connected to the fourth end, and the third end is connected to the molten salt outlet; The first molten salt channel is used to guide the primary molten salt to flow through the core from bottom to top, and the second molten salt channel is used to guide the primary molten salt to flow through the core from top to bottom.

[0008] In a possible implementation, the core includes a first fuel pipeline and a second fuel pipeline, and the second fuel pipeline is sleeved outside the first fuel pipeline; The inner space of the first fuel pipeline is formed as the first molten salt channel, and the space between the first fuel pipeline and the second fuel pipeline is formed as the second molten salt channel; or the inner space of the first fuel pipeline is formed as the second molten salt channel, and the space between the first fuel pipeline and the second fuel pipeline is formed as the first molten salt channel.

[0009] In a possible implementation, the core includes a first fuel pipeline and a second fuel pipeline, and one end of the first fuel pipeline is connected to one end of the second fuel pipeline; The inner space of the first fuel pipeline is formed as the first molten salt channel, and the inner space of the second fuel pipeline is formed as the second molten salt channel; or the inner space of the first fuel pipeline is formed as the second molten salt channel, and the inner space of the second fuel pipeline is formed as the first molten salt channel.

[0010] In a possible implementation, the heavy water moderated molten salt reactor further includes: A molten salt discharge system, the molten salt discharge system comprising a molten salt discharge pipeline, a molten salt discharge valve and a molten salt storage tank, the molten salt discharge valve being arranged on the molten salt discharge pipeline, the molten salt discharge pipeline having a molten salt discharge inlet and a molten salt discharge outlet, wherein the molten salt discharge inlet is connected to the molten salt inlet and the molten salt outlet, and the molten salt discharge outlet is connected to the molten salt storage tank.

[0011] In a possible implementation, the core includes a plurality of molten salt channels with different diameters, and the center distances between adjacent molten salt channels are the same.

[0012] In a possible implementation, the core further includes control rods, which are arranged in the heavy water between the molten salt channels.

[0013] A possible implementation also includes: A heavy water reflecting layer is located in the reactor vessel, and the heavy water reflecting layer wraps around the periphery of the core.

[0014] In a possible implementation, the reactor vessel has a heavy water inlet and a heavy water outlet, and the heavy water outlet is located at the lower part of the reactor vessel; the heavy water moderated molten salt reactor further includes: A heavy water circulation and discharge system, comprising a heavy water circulation pipeline, a heavy water circulation pump, a first heat exchanger, a heavy water discharge pipeline, a heavy water discharge valve, and a heavy water storage tank, wherein the heavy water circulation pipeline is connected between the heavy water inlet and the heavy water outlet; one end of the heavy water discharge pipeline is connected to the heavy water outlet, and the other end is connected to the heavy water storage tank; the heavy water circulation pump and the first heat exchanger are arranged on the heavy water circulation pipeline, and the heavy water discharge valve is arranged on the heavy water discharge pipeline.

[0015] A possible implementation also includes: A molten salt circulation pipeline connected between the molten salt inlet and the molten salt outlet; A main heat exchanger, located on the molten salt circulation pipeline; A primary circuit main pump is located on the molten salt circulation pipeline; The secondary side waste heat removal system comprises an electric valve, a pneumatic valve and a second heat exchanger. The inlet pipe of the secondary side waste heat removal system is connected to the secondary side outlet of the main heat exchanger. The electric valve and the pneumatic valve are located between the secondary side outlet and the second heat exchanger.

[0016] Compared with the prior art, this application has the following advantages: The heavy water moderated molten salt reactor provided in the present application includes a reactor vessel and a core, the reactor vessel has a molten salt inlet and a molten salt outlet, and the molten salt inlet and the molten salt outlet are both located at the lower part of the reactor vessel; the core is located in the reactor vessel, and the core includes a molten salt channel and heavy water, the heavy water wraps the molten salt channel, and the molten salt channel is connected between the molten salt inlet and the molten salt outlet. The present application adopts liquid heavy water instead of solid graphite as a moderator, which on the one hand meets the moderation requirements of the molten salt reactor, and on the other hand can also solve the problem of radiation swelling and regular replacement of solid moderator materials, thereby improving the intrinsic safety of nuclear power plants. In addition, the inlet and outlet of the primary circuit molten salt are both located at the lower part of the reactor vessel, which saves the upper space of the reactor vessel and is conducive to the arrangement of other equipment such as the control rod drive mechanism at the upper part of the core. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings: Figure 1 It is a structural schematic diagram of a heavy water moderated molten salt reactor provided in an embodiment of the present application; Figure 2 It is a structural schematic diagram of a molten salt discharge system provided in an embodiment of the present application; Figure 3It is a structural schematic diagram of a molten salt channel provided in an embodiment of the present application; Figure 4 is a schematic structural diagram of another molten salt channel provided in an embodiment of the present application; Figure 5 It is a schematic diagram of the radial structure of a core provided in an embodiment of the present application; Figure 6 It is a structural schematic diagram of a heavy water circulation and sorting system provided in an embodiment of the present application; Figure 7 It is a structural schematic diagram of a secondary side waste heat removal system provided in an embodiment of the present application.

[0018] In the figure: 100, heavy water moderated molten salt reactor; 101, primary loop system; 102, secondary loop system; 103, tertiary loop system; 111, reactor vessel; 1111, molten salt inlet; 1112, molten salt outlet; 1113, heavy water inlet; 1114, heavy water outlet; 112, core; 1121, molten salt channel; 1122, heavy water holding chamber; 1123, control rod; 1124, inner space; 1125, outer space; 1211, first molten salt channel; 1212, second molten salt channel; 113, molten salt circulation pipeline; 114, main heat exchanger; 115, primary loop main pump; 116, heavy water reflector; 110, molten salt discharge system; 120, heavy Water circulation and discharge system; 130, secondary side waste heat removal system; 121, steam generator; 122, secondary loop circulation pump; 1101, molten salt discharge pipeline; 1102, molten salt discharge valve; 1103, molten salt storage tank; 201, first fuel pipeline; 202, second fuel pipeline; 2011, first end; 2012, second end; 2021, third end; 2022, fourth end; 1201, heavy water circulation pipeline; 1202, heavy water circulation pump; 1203, first heat exchanger; 1204, heavy water discharge pipeline; 1205, heavy water discharge valve; 1206, heavy water storage tank; 1301, electric valve; 1302, pneumatic valve; 1303, second heat exchanger. DETAILED DESCRIPTION

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0020] As shown in this application, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0021] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0022] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0023] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0024] In addition, it should be noted that the use of words such as "first" and "second" to limit objects is only for the convenience of distinguishing the corresponding objects. If not otherwise stated, the above words have no special meanings and therefore cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from commonly known and commonly used terms, some of the terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0025] It should be understood that when a component is referred to as being "on another component," "connected to another component," "coupled to another component," or "contacting another component," it may be directly on, connected to, coupled to, or contacting the other component, or there may be intervening components. In contrast, when a component is referred to as being "directly on another component," "directly connected to," "directly coupled to," or "directly contacting" another component, there are no intervening components. Similarly, when a first component is referred to as being "electrically in contact with" or "electrically coupled to" a second component, there is an electrical path between the first component and the second component that allows current to flow. The electrical path may include capacitors, coupled inductors, and / or other components that allow current to flow, even without direct contact between conductive components.

[0026] Existing molten salt reactors usually use graphite as a moderator. In a graphite-moderated liquid fuel molten salt reactor, nuclear-grade graphite is in direct contact with the fuel molten salt and must meet requirements such as high purity, high density, low porosity, high strength, and high irradiation stability. At the same time, as the irradiation dose accumulates, the graphite will swell and crack, destroying the structural stability. Therefore, the graphite components in the core must be replaced regularly during the life of the molten salt reactor. Since the primary circuit system of the molten salt reactor contains a large amount of highly radioactive materials, the graphite replacement project is quite challenging.

[0027] The embodiment of the present application adopts liquid heavy water instead of solid graphite as a moderator, which on the one hand meets the moderation requirements of the molten salt reactor, and on the other hand can also solve the problem of radiation swelling and regular replacement of solid moderator materials, thereby improving the intrinsic safety of nuclear power plants.

[0028] Figure 1 Schematic diagram of the structure of a heavy water moderated molten salt reactor provided in the embodiment of the present application. Figure 1As shown, the heavy water moderated molten salt reactor 100 includes a primary loop system 101, a secondary loop system 102 and a tertiary loop system 103. The primary loop system 101 is used to generate heat, and the secondary loop system 102 is used to transfer the heat generated by the primary loop system 101 to the tertiary loop system 103. The tertiary loop system 103 can be used for comprehensive utilization of nuclear energy such as power generation, heat supply, steam supply, device power supply, and seawater desalination.

[0029] The primary loop system 101 includes a reactor vessel 111, a core 112, a molten salt circulation pipeline 113, a main heat exchanger 114, and a primary loop main pump 115. The main heat exchanger 114 and the primary loop main pump 115 are both located on the molten salt circulation pipeline 113, and the reactor vessel 111, the main heat exchanger 114, and the primary loop main pump 115 are connected through the molten salt circulation pipeline 113. In a specific embodiment, the primary loop system 101 relies on the primary loop main pump 115 to provide a forced circulation driving force. The liquid molten salt in the primary loop system 101 is both a fuel and a coolant. It operates at normal pressure. The molten salt flows through the core 112 through the molten salt channel to generate heat, and takes the heat out of the core 112, enters the main heat exchanger 114 through the molten salt circulation pipeline 113, and transfers the heat to the secondary loop molten salt. Then, the primary loop molten salt enters the core 112 through the primary loop main pump 115. The secondary loop system 102 includes a steam generator 121 and a secondary loop circulation pump 122. The secondary loop system 102 relies on the secondary loop circulation pump 122 to provide forced circulation driving force. The secondary loop molten salt does not contain fuel and operates at normal pressure. The secondary loop molten salt is heated in the main heat exchanger 114 and then flows into the steam generator 121, transferring heat to the tertiary loop working fluid, and then returns to the inlet of the main heat exchanger 114 through the secondary loop circulation pump 122.

[0030] It is understood that the heavy water moderated molten salt reactor 100 is not limited to the structure of this embodiment, but may have different variations. For example, some components may be changed or omitted, or additional components may be added.

[0031] Please refer to Figure 1-Figure 2 , the core 112 is located in the reactor vessel 111. The core 112 includes a molten salt channel 1121 and a heavy water holding chamber 1122. The heavy water holding chamber 1122 is filled with heavy water and wraps the molten salt channel 1121. The molten salt channel 1121 is used to provide a channel for the flow of a loop of molten salt. In some embodiments, the reactor vessel 111 has a molten salt inlet 1111 and a molten salt outlet 1112. The molten salt channel 1121 is connected between the molten salt inlet 1111 and the molten salt outlet 1112. The molten salt inlet 1111 and the molten salt outlet 1112 are both located at the lower part of the reactor vessel 111. The molten salt circulation pipeline 113 is connected between the molten salt inlet 1111 and the molten salt outlet 1112.

[0032] In an exemplary embodiment, please refer to Figure 2-Figure 5The molten salt channel 1121 includes a first molten salt channel 1211 and a second molten salt channel 1212. The first molten salt channel 1211 has a first end 2011 and a second end 2012, and the second molten salt channel 1212 has a third end 2021 and a fourth end 2022. The first end 2011 is connected to the molten salt inlet 1111, the second end 2012 is connected to the fourth end 2022, and the third end 2021 is connected to the molten salt outlet 1112. The first molten salt channel 1211 is used to guide the primary molten salt to flow from bottom to top through the core 112, and the second molten salt channel 1212 is used to guide the primary molten salt to flow from top to bottom through the core 112.

[0033] For example, the primary molten salt enters the reactor vessel 111 through the molten salt inlet 1111, flows through the core 112 from bottom to top through the first molten salt channel 1211, and turns to flow through the core 112 from top to bottom again through the second molten salt channel 1212 after reaching the top of the core 112. After reaching the lower end of the second molten salt channel 1212, the primary molten salt flows out of the reactor vessel 111 through the molten salt outlet 1112. The primary molten salt undergoes a fission reaction in the process of flowing through the first molten salt channel 1211 and the second molten salt channel 1212 to generate heat, and the heat is taken out of the core 112 through the flow.

[0034] In the embodiment of the present application, the inlet and outlet of the primary molten salt loop are both located at the lower part of the reactor vessel 111, which saves the upper space of the reactor vessel 111 and is conducive to arranging other equipment such as the control rod drive mechanism on the upper part of the core 112. Figure 2 As shown, the core 112 also includes control rods 1123, and the control rods 1123 are partially arranged in the heavy water containing chamber 1122 between the molten salt channels 1121. The control rods 1123 can be inserted or lifted up in the heavy water containing chamber 1122, and the reactivity of the core 112 is controlled by inserting or lifting. In the event of an accident, the control rod drive mechanism is powered off, and the control rods 1123 can be inserted into the core 112 by gravity, so that the molten salt reactor is shut down passively. The control rods 1123 are arranged in the heavy water containing chamber between the molten salt channels, which does not affect the fuel arrangement in the reactor and improves the reactivity control capability.

[0035] In some embodiments, the core 112 includes a first fuel pipe 201 and a second fuel pipe 202 to form a first molten salt channel 1211 and a second molten salt channel 1212. Figure 3In one embodiment, the second fuel pipeline 202 is sleeved outside the first fuel pipeline 201, the internal space of the first fuel pipeline 201 is formed as the first molten salt channel 1211, and the space between the first fuel pipeline 201 and the second fuel pipeline 202 is formed as the second molten salt channel 1212. It can be understood that in some other embodiments, the internal space of the first fuel pipeline 201 can also be formed as the second molten salt channel 1212, and the space between the first fuel pipeline 201 and the second fuel pipeline 202 can be formed as the first molten salt channel 1211.

[0036] Please refer to Figure 4 In another embodiment, the first fuel pipeline 201 and the second fuel pipeline 202 are arranged side by side, and one end of the first fuel pipeline 201 is connected to one end of the second fuel pipeline 202. The internal space of the first fuel pipeline 201 is formed as a first molten salt channel 1211, and the internal space of the second fuel pipeline 202 is formed as a second molten salt channel 1212. It can be understood that in some other embodiments, the internal space of the first fuel pipeline 201 can also be formed as the second molten salt channel 1212, and the internal space of the second fuel pipeline 202 can be formed as the first molten salt channel 1211.

[0037] Continue to refer Figure 1 The heavy water moderated molten salt reactor 100 further includes a molten salt discharge system 110. The molten salt discharge system 110 is connected to the lower part of the reactor vessel 111. Under some serious accident conditions, the molten salt discharge system 110 is started, and the primary molten salt in the core 112 is discharged by gravity, the molten salt reactor is safely shut down, and the residual heat in the primary molten salt is removed.

[0038] In some embodiments, please refer to Figure 2 The molten salt discharge system 110 includes a molten salt discharge pipeline 1101, a molten salt discharge valve 1102 and a molten salt storage tank 1103. The molten salt discharge valve 1102 is arranged on the molten salt discharge pipeline 1101. The molten salt discharge pipeline 1101 has a molten salt discharge inlet and a molten salt discharge outlet, wherein the molten salt discharge inlet is connected to the molten salt inlet 1111 and the molten salt outlet 1112, and the molten salt discharge outlet is connected to the molten salt storage tank 1103. In this embodiment, the molten salt inlet 1111 and the molten salt outlet 1112 are both located at the lower part of the reactor vessel 111, and the molten salt discharge inlet is connected to the molten salt inlet 1111 and the molten salt outlet 1112 at the same time. Under accident conditions, the molten salt inlet 1111 and the molten salt outlet 1112 can be used for molten salt discharge, which is conducive to molten salt discharge and improves safety.

[0039] For example, the molten salt discharge system 110 includes two molten salt discharge valves 1102, which are respectively arranged between the molten salt inlet 1111 and the molten salt storage tank 1103, and the molten salt outlet 1112 and the molten salt storage tank 1103. Specifically, a molten salt discharge pipeline 1101 is connected in parallel at the molten salt inlet 1111 and the molten salt outlet 1112, connected to the molten salt discharge valve 1102, and then connected to the molten salt storage tank 1103. In some embodiments, the molten salt discharge valve 1102 is a freezing valve. During normal operation, the molten salt discharge valve 1102 is in a normally closed state. Under accident conditions, the molten salt temperature rises, and the molten salt discharge valve 1102 is triggered to open due to the high temperature. The primary molten salt is discharged through the parallel molten salt discharge pipeline 1101 at the molten salt inlet 1111 and the molten salt outlet 1112, and enters the molten salt storage tank 1103 through the molten salt discharge valve 1102. The molten salt in the core 112 is emptied, the molten salt reactor is safely shut down, and the residual heat in the molten salt is discharged through the residual heat discharge system of the molten salt storage tank 1103. In some other embodiments, the molten salt discharge valve 1102 is a solenoid valve. During normal operation, the molten salt discharge valve 1102 is in a normally closed state. Under accident conditions, the molten salt discharge valve 1102 is opened when the power is lost.

[0040] In some embodiments, please refer to Figure 5 , the core 112 includes a plurality of molten salt channels 1121 with different diameters, and the center distances between adjacent molten salt channels 1121 are the same. It should be noted that, Figure 5 As shown, when the first fuel pipeline 201 and the second fuel pipeline 202 are arranged inside and outside, the first fuel pipeline 201 and the second fuel pipeline 202 arranged together are regarded as a fuel main pipeline, and the center distance between two adjacent fuel main pipelines is the center distance between adjacent molten salt channels 1121. When the first fuel pipeline 201 and the second fuel pipeline 202 are arranged side by side, as shown in FIG. Figure 4 As shown, the first fuel pipeline 201 and the second fuel pipeline 202 are both separate fuel pipelines, and the center distance between two adjacent separate fuel pipelines is the center distance between adjacent molten salt channels.

[0041] In a specific embodiment, the primary molten salt flows through the core 112 from bottom to top via the first molten salt channel 1211 in the first fuel pipeline 201, and flows through the core 112 from top to bottom via the second molten salt channel 1212 between the first fuel pipeline 201 and the second fuel pipeline 202. The outside of the second fuel pipeline 202 is a heavy water storage space (such as a heavy water storage chamber 1122), thus forming a core grid. The core 112 is composed of a plurality of such grids arranged together, and the grids in the core 112 can be arranged in a square or hexagonal form. The center distances between all adjacent grids in the core 112 are the same, that is, the center distances between adjacent molten salt channels 1121 are the same.

[0042] The internal space of the core 112 includes an inner space 1124 ( Figure 5 The space within the dotted circle) and outer space 1125 ( Figure 5 The outer space 1125 surrounds the inner space 1124. In some embodiments, the diameter of the molten salt channel 1121 in the inner space 1124 of the core 112 is smaller, so as to obtain better moderation, so as to improve the effective proliferation factor of the core 112; the diameter of the molten salt channel 1121 in the outer space 1125 of the core 112 is larger, so as to obtain a better fuel proliferation effect. For example, the diameter of the first molten salt channel 1211 in the inner space 1124 of the core 112 is smaller than the diameter of the first molten salt channel 1211 in the outer space 1125 of the core 112, and the diameter of the second molten salt channel 1212 in the inner space 1124 of the core 112 is smaller than the diameter of the second molten salt channel 1212 in the outer space 1125 of the core 112, while the ratio of the diameter of the first molten salt channel 1211 in the core 112 to the diameter of the second molten salt channel 1212 can remain unchanged. In some other embodiments, the diameter of the molten salt channel 1121 in the inner space 1124 of the core 112 may be larger, and the diameter of the molten salt channel 1121 in the outer space 1125 of the core 112 may be smaller, or the molten salt channel 1121 with a larger diameter and the molten salt channel 1121 with a smaller diameter may be arranged alternately from the inside to the outside, or the diameter of the molten salt channel 1121 may increase or decrease in sequence from the inside to the outside, so as to adjust the fuel-moderator ratio and achieve the purpose of flattening the power distribution and changing the proliferation ratio. For example, the diameter of the first molten salt channel 1211 in the inner space 1124 of the core 112 is larger than the diameter of the first molten salt channel 1211 in the outer space 1125 of the core 112, and the diameter of the second molten salt channel 1212 in the inner space 1124 of the core 112 is larger than the diameter of the second molten salt channel 1212 in the outer space 1125 of the core 112. It can be understood that the division of the inner space 1124 and the outer space 1125 of the core 112 is not limited to Figure 5 The embodiment shown, Figure 5 The embodiments shown are for illustrative purposes only.

[0043] The heavy water moderated molten salt reactor 100 further includes a heavy water reflector 116 located in the reactor vessel 111 . The heavy water reflector 116 wraps around the periphery of the core 112 to reduce leakage and improve neutron economy.

[0044] Continue to refer Figure 1The reactor vessel 111 has a heavy water inlet 1113 and a heavy water outlet 1114, and the heavy water outlet 1114 is located at the lower part of the reactor vessel 111. The heavy water moderated molten salt reactor 100 also includes a heavy water circulation and discharge system 120 connected between the heavy water inlet 1113 and the heavy water outlet 1114. The heavy water can be better discharged through circulation, and the heavy water can also be kept at a high purity through circulation purification. Under some accident conditions that require rapid shutdown, the heavy water circulation and discharge system 120 is started, the heavy water in the reactor vessel 111 is emptied by gravity, and the molten salt reactor is safely shut down.

[0045] In some embodiments, please refer to Figure 6 The heavy water circulation and discharge system 120 includes a heavy water circulation pipeline 1201, a heavy water circulation pump 1202, a first heat exchanger 1203, a heavy water discharge pipeline 1204, a heavy water discharge valve 1205 and a heavy water storage tank 1206. The heavy water circulation pipeline 1201 is connected between the heavy water inlet 1113 and the heavy water outlet 1114. One end of the heavy water discharge pipeline 1204 is connected to the heavy water outlet 1114, and the other end is connected to the heavy water storage tank 1206. The heavy water circulation pump 1202 and the first heat exchanger 1203 are arranged on the heavy water circulation pipeline 1201, and the heavy water discharge valve 1205 is arranged on the heavy water discharge pipeline 1204.

[0046] Specifically, the heavy water in the reactor vessel 111 provides a neutron moderation function for the core 112 and generates some heat at the same time. The heavy water circulation and discharge system 120 relies on the heavy water circulation pump 1202 to provide a forced circulation driving force. The heavy water flows out from the heavy water outlet 1114 at the bottom of the reactor vessel 111, flows into the first heat exchanger 1203 through the heavy water circulation pump 1202, and the excess heat in the heavy water is discharged. The cooled heavy water returns to the reactor vessel 111 through the top of the core 112. A heavy water outlet 1114 at the bottom of the reactor vessel 111 is connected in parallel with a heavy water discharge pipe 1204 to a heavy water discharge valve 1205. During normal operation, the heavy water discharge valve 1205 is in a normally closed state. Under accident conditions, the heavy water discharge valve 1205 is opened, and the heavy water in the reactor vessel 111 is discharged through the heavy water discharge pipe 1204 connected to the heavy water outlet 1114, and enters the heavy water storage tank 1206 through the heavy water discharge valve 1205. The heavy water in the reactor vessel 111 is emptied without external power, the core 112 loses moderation, and the molten salt reactor is safely shut down.

[0047] Continue to refer Figure 1 The heavy water moderated molten salt reactor 100 further includes a secondary side residual heat removal system 130. The secondary side residual heat removal system 130 is connected in parallel to the main heat exchanger 114. Under some accident conditions, the secondary side residual heat removal system 130 is started to remove the core residual heat through natural circulation.

[0048] In some embodiments, please refer to Figure 7 , the secondary side waste heat removal system 130 includes an electric valve 1301, a pneumatic valve 1302 and a second heat exchanger 1303. The inlet pipe of the secondary side waste heat removal system 130 is connected to the secondary side outlet of the main heat exchanger 114, and the electric valve 1301 and the pneumatic valve 1302 are located between the secondary side outlet and the second heat exchanger 1303. The secondary side waste heat removal system 130 may include one or more parallel pneumatic valves 1302 to improve safety. For example, the secondary side waste heat removal system 130 includes a normally open electric valve 1301 and two parallel normally closed pneumatic valves 1302. The pneumatic valve 1302 opens when the power is lost, and the secondary side waste heat removal system 130 starts, relying on natural circulation to remove the waste heat in the core 112. This design of non-active waste heat removal greatly improves the safety of the molten salt reactor.

[0049] Specifically, during normal operation, the electric valve 1301 is in a normally open state and the pneumatic valve 1302 is in a normally closed state. During maintenance, the electric valve 1301 is manually closed to prevent the system from malfunctioning. Under accident conditions, the pneumatic valve 1302 is opened, and the residual heat of the core is naturally circulated through the first loop and transferred to the second loop molten salt via the main heat exchanger 114. The secondary side residual heat removal system 130 transfers heat to the second heat exchanger 1303 through natural circulation. The second heat exchanger 1303 is immersed in a water tank and removes heat through the evaporation of water, so that no one can intervene for a long time after the accident. The secondary side residual heat removal system 130 is a dedicated safety facility and a safety-related system that can discharge the residual heat of the core and achieve in-depth defense when the normal residual heat removal function fails and the loop can operate normally.

[0050] In the above embodiment, the secondary side waste heat removal system 130 adopts water cooling, and the final heat sink is a water tank. In some other embodiments, the secondary side waste heat removal system 130 may also adopt other cooling methods, such as air cooling, and the final heat sink is the atmosphere. The molten salt working fluid in the system directly discharges heat to the atmosphere through an air cooling tower. Relying on the natural temperature difference between molten salt and air, a non-active circulation loop is designed, and natural convection and natural circulation mechanisms are utilized. By optimizing the configuration of the molten salt loop pipe diameter, direction, and position of the heat exchanger, it is ensured that the molten salt can flow spontaneously, continuously and stably without external power, forming an efficient heat transfer path, greatly improving the waste heat removal efficiency, and reducing the risk of mechanical failure.

[0051] The embodiments of the present application fully implement the passive safety concept, and further propose safety systems such as the molten salt discharge system 110, the heavy water circulation and discharge system 120, and the secondary side residual heat removal system 130, so as to realize the reactivity control and core residual heat removal after the molten salt reactor accident in a passive manner, thereby improving the safety of the heavy water moderated molten salt reactor.

[0052] The heavy water moderated molten salt reactor of the embodiment of the present application includes three sets of reactivity control systems. The first set is the control rod system, which controls the insertion or withdrawal of the neutron absorber into the core through the control rod drive mechanism to achieve the purpose of reactivity control. In the event of an accident, the control rod relies on the energy storage device to quickly insert the core to shut down the molten salt reactor passively. The second set is the heavy water circulation and discharge system, which changes the neutron moderation capacity of the core through the change of the heavy water level in the reactor vessel to achieve the purpose of reactivity control. In the event of an accident, the heavy water discharge valve loses power and opens, causing the molten salt reactor to shut down passively. The third set is the molten salt discharge system, which achieves the purpose of reactivity control by discharging the fuel molten salt (i.e., the primary circuit molten salt) from the core. In the event of an accident, the molten salt is quickly discharged into the molten salt storage tank through the molten salt discharge valve, causing the molten salt reactor to shut down passively. All three systems adopt a passive design, and the working principles are different, which avoids common cause failures and improves the safety of the molten salt reactor.

[0053] The basic concepts have been described above. Obviously, for those skilled in the art, the above invention disclosure is only used as an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0054] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0055] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of the present application, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the subject of the present application requires more features than the features mentioned. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above.

[0056] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present application, they will fall within the scope of the present application.

Claims

1. A heavy water moderated molten salt reactor, characterized in that: include: A reactor vessel having a molten salt inlet and a molten salt outlet, wherein the molten salt inlet and the molten salt outlet are both located at a lower portion of the reactor vessel; A core is located in the reactor vessel, the core comprising a molten salt channel and a heavy water containing space, the heavy water containing space wraps the molten salt channel and is filled with heavy water, and the molten salt channel is connected between the molten salt inlet and the molten salt outlet.

2. The heavy water moderated molten salt reactor according to claim 1, characterized in that: The molten salt channel comprises a first molten salt channel and a second molten salt channel, the first molten salt channel has a first end and a second end, the second molten salt channel has a third end and a fourth end, the first end is communicated with the molten salt inlet, the second end is communicated with the fourth end, and the third end is communicated with the molten salt outlet; The first molten salt channel is used to guide the primary molten salt to flow through the core from bottom to top, and the second molten salt channel is used to guide the primary molten salt to flow through the core from top to bottom.

3. The heavy water moderated molten salt reactor according to claim 2, characterized in that: The core comprises a first fuel pipeline and a second fuel pipeline, wherein the second fuel pipeline is sleeved outside the first fuel pipeline; The inner space of the first fuel pipeline is formed as the first molten salt channel, and the space between the first fuel pipeline and the second fuel pipeline is formed as the second molten salt channel; or the inner space of the first fuel pipeline is formed as the second molten salt channel, and the space between the first fuel pipeline and the second fuel pipeline is formed as the first molten salt channel.

4. The heavy water moderated molten salt reactor according to claim 2, characterized in that: The core includes a first fuel pipeline and a second fuel pipeline, one end of the first fuel pipeline is connected to one end of the second fuel pipeline; The inner space of the first fuel pipeline is formed as the first molten salt channel, and the inner space of the second fuel pipeline is formed as the second molten salt channel; or the inner space of the first fuel pipeline is formed as the second molten salt channel, and the inner space of the second fuel pipeline is formed as the first molten salt channel.

5. The heavy water moderated molten salt reactor according to claim 1, characterized in that: Also includes: A molten salt discharge system, the molten salt discharge system comprising a molten salt discharge pipeline, a molten salt discharge valve and a molten salt storage tank, the molten salt discharge valve being arranged on the molten salt discharge pipeline, the molten salt discharge pipeline having a molten salt discharge inlet and a molten salt discharge outlet, wherein the molten salt discharge inlet is connected to the molten salt inlet and the molten salt outlet, and the molten salt discharge outlet is connected to the molten salt storage tank.

6. The heavy water moderated molten salt reactor according to claim 1, characterized in that: The core includes a plurality of molten salt channels with different diameters, and the center distances between adjacent molten salt channels are the same.

7. The heavy water moderated molten salt reactor according to claim 1, characterized in that: The core also includes control rods disposed in the heavy water between the molten salt channels.

8. The heavy water moderated molten salt reactor according to claim 1, characterized in that: Also includes: A heavy water reflecting layer is located in the reactor vessel, and the heavy water reflecting layer wraps around the periphery of the core.

9. The heavy water moderated molten salt reactor according to any one of claims 1 to 8, characterized in that: The reactor vessel has a heavy water inlet and a heavy water outlet, and the heavy water outlet is located at the lower part of the reactor vessel; the heavy water moderated molten salt reactor also includes: A heavy water circulation and discharge system, comprising a heavy water circulation pipeline, a heavy water circulation pump, a first heat exchanger, a heavy water discharge pipeline, a heavy water discharge valve, and a heavy water storage tank, wherein the heavy water circulation pipeline is connected between the heavy water inlet and the heavy water outlet; one end of the heavy water discharge pipeline is connected to the heavy water outlet, and the other end is connected to the heavy water storage tank; the heavy water circulation pump and the first heat exchanger are arranged on the heavy water circulation pipeline, and the heavy water discharge valve is arranged on the heavy water discharge pipeline.

10. The heavy water moderated molten salt reactor according to any one of claims 1 to 8, characterized in that: Also includes: A molten salt circulation pipeline connected between the molten salt inlet and the molten salt outlet; A main heat exchanger, located on the molten salt circulation pipeline; A primary circuit main pump is located on the molten salt circulation pipeline; The secondary side waste heat removal system comprises an electric valve, a pneumatic valve and a second heat exchanger. The inlet pipe of the secondary side waste heat removal system is connected to the secondary side outlet of the main heat exchanger. The electric valve and the pneumatic valve are located between the secondary side outlet and the second heat exchanger.

Images